/**
 * Copyright 2009 Erick Armbrust 
 * Licensed under the Apache License, Version 2.0 (the "License"); 
 * you may not use this file except in compliance with the License. 
 * You may obtain a copy of the License at 
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0 
 *   
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the License is distributed on an "AS IS" BASIS, 
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
 * See the License for the specific language governing permissions and 
 * limitations under the License. 
 */

package tapioca.util;

import com.google.appengine.api.datastore.Key;

public class KeyUtil {

  private KeyUtil() {}
  
  public static Key getRootKey(Key key) {
    Key rootKey = key;
    while (rootKey.getParent() != null) {
      rootKey = rootKey.getParent();
    }
    return rootKey;
  }
  
  public static boolean inSameEntityGroup(Key... keys) {
    Key entityGroupKey = null;
    
    for (Key key : keys) {
      Key currentRootKey = getRootKey(key);
      
      if (entityGroupKey == null) {
        entityGroupKey = currentRootKey;
      } else if (!entityGroupKey.equals(currentRootKey)) {
        return false;
      }
    }
    
    return true;
  }
  
}
